Use of environmentally unfriendly anti-freeze solutions, such as ethylene glycol, to de-ice aircraft on airport aprons is under review in the light of proposals that more frequent de-icing processes be implemented following recent tragic airplane crashes believed to be caused by icing on the plane during periods of waiting on the apron. Thus, de-icing materials have attracted the attention of governmental environmental agencies because of the inability of the airlines to recover acceptable amounts of the spilled anti-freeze materials, particularly ethylene glycol, from the airport apron after a plane has been de-iced.
It is recognized that there is a serious problem in finding a method and equipment to recover the wasted anti-freeze off the apron. There are motorized road sweeping and catchbasin vehicles in use on airport aprons to remove materials such as snow, ice, small debris and the like and surface liquid. One known type of such vehicle utilizes a clockwise rotating broom disposed at an angle to the forward direction of the moving vehicle to direct such materials to a vacuum head which sucks the materials into a waste holding compartment. However, it has been found that unsatisfactory and potentially unacceptable amounts of anti-freeze chemical remain on the surface of the apron. The apron remains overly slippery and reduces good traction to aircraft and personnel, and, thus creates a safety hazard. More importantly, with a film of ethylene glycol still on the apron when rain or water hits the apron area, the water miscible glycol and water mixture runs off into the soil and eventually enters the water table. Such runoff is becoming increasingly unacceptable to governmental environmental agencies.
Alternative motorized vehicles for use on airport aprons having merely a straight vacuum head without a rotating broom have been used. Without the broom, the vacuum head has been significantly enlarged. A further alternative mechanical sweeping vehicle is known with a vacuum head trailing the vehicle. Yet a further alternative sweeping and catching motorized vehicle for use on airport aprons is known which has an eight foot sponge rotatable on the surface of the apron to absorb the anti-freeze mixture while another roller squeezes the sponge to release any fluid collected into a holding tank.
Notwithstanding the various attempts at solving the apparently simple problem of picking up solid and semi-solid objects such as slush, ice, snow, small debris and the like and surface liquids, such as water, glycol, and oil, to-date no satisfactory environmentally acceptable method and machine for use therein are known. There thus remains a demand for apparatus and methods for rapidly and effectively removing anti-freeze solutions from road surfaces which do not cause subsequent environmental problems.